Valve-gear.



G. K. DAVOL.

VALVE GEAR.

APPLICATION FILED NOV. 12, 1912.

4 SHEETS-SHEET I.

m FIG 5 a WITNESSES IN V ENTOR Geor geff. Dauo l/ m Mh/M WWW ATTORNEY5 G. K. DAVOL.

VALVE GEAR.

APPUCATION FILED Nov. 12. 1912.

Patented Nov. 16, 1915.

4 SHEETSSHEET 2.

W [TN ESSES VFM I 660796 2522 06 M fmwmwmmwfimu ATTORNEYS COLUMBIA PLANOG G. K. DAVOL.

VALVE GEAR.

APPLICATION r1150 NOV. 12. 1912. 1,160,582. Patented Nov. 16, 1915. 1 4 SHEETS-SHEET 4.

FIG 10 76 I 2'8 I l i 2 44- 1 I: i I l/ \f 1 1 0' 7? T FIB ll FIG 12 J 62 6 a:

WITNESSES INVENTOR $1M Gear e Zf-DcumZ/ 4 M 5 6W1 MM M M ATTORNEY5 re r - wi l ee ie? enonenii. navonforshn FRANCISCOfOALIFOR-ifirk.

VALVE-GEAR.

'1Applicationliled November12, 1912. 'seriarnm30,sa2. a

,7?) [Z whom it may concern 3 .v i

Be it known thatI, Gnomes K. DAV L, a citizen of the, United States, residing in the city and county vof San Francisco, "in. the State of California,have invented a, cer; tain new and useful form of jvalveeGear for Engines,of which the. following is a speoifi; cation. a My invention relates to a form of valve gear designed to have particular application to interi'ial combustion enginesl This form of valve gear which embodies my invention can be applied to inany different forms of internal combustion engines and also to steam and other fluid pressure engines, but, as itisdesigned torhave particular application toithe tWo-strokecycle internal coinbustionengine, invvhich fuel is injected into the cylinder at the beginning of the ivorkinglstroke, I Will confineinyself inthcse specifications to describing the gear in this application, althoughother applications, of the valve gear vwill of course be evident. y

In anengine'of the class above indicated the usual functions of: avalveigear: are as follows: 1.-Operationuof the fuelv valve. 2.Operation of the scavenging valve or valves. 3.,- Operation of the starting valve. l.@;pera.tion of a compression relief valve, or operating the scavenging valves so as to relieve compression at starting.

The exhaust in .an engine of this, class usually takes place through ports in the cylinder Walls which are overrun by the, working piston'and therefore the valve gear; is. not ordinarily called upon to operate ex haust valves Invanenginevofthe. class re; ferred to, air is, compressedin. the cylinder by the inward stroke of the piston and at or near the point of highestieompression,the fuel valve is opened and fuel injected into. the cylinder, after, \vliich the working stroke. fell 0 W s. Shortly afteizthe egrhaustg ports, are, uncovered. by the piston,, the scavenging; valves are opened and scavenging airforced; into or through the cylinder, .displacingthe products of combustion. is The compression stroke then vfollows. c For starting, thefuel valve is ordinarilythrovvn out of gear andv the engine operated by compressed airtuntil it attains a suitablelspeed, Whenthe oonn pressed air is diseontinued and the vfuelv valve thrown into; gear. a When -,,operating; on compressed air, .it is advantageous that the degree of compressionpf the,ain lathe,

Working cylinder be n cderatedfor, in other Words, the compression relieved. This may beaccomplished by holding open the scavcnging valves for thevrhole or a portion of so What, in full running, gear, constitutes the' compression stroke. These var ous fund tions can be accomplished if, the mid-point of the opening and closing of the fuel valve 7 at 180 degrees from the mid-point of the 5 opening and closing of the scavenging valves, and when starting on compressed air, if the mid-point of the opening and closing l v of the starting valve beatlSO degrees from. the mid-point of theopening and 7e closin of the scavenging valves, the 18Qdegrees being referred of course to the revolution of the main crank of engine, "When running on compressed air at starting, it is usually desirable, however, that the air valve be opened for a longer period than that which embraces the openingof the fuel valve when running on fuel, alsoiivhen start ing it is desirable that the scavenging, be heldopen longer than when runnin fuel, in order to relieve the compression on thecylinder, as aboveanentioned. Fo ,eversing the engine and for starting, it: is necessary that the points of opening and closing the fuel valve, scavenging valve and starting air valve be varied ithreference to the crank of the "engine; It is alsoj sirable that the angular pesition of the points of theopcning and closing of the fuel valvebe susceptible of: variation when: runs ningon fuel. In addition, therefore, to the four operating functions hereinbefore list; 1

edthe valve gear is callednpori to afford a means of varying the angularpc ition' with referenceto the cra-nkf pin of the engins of the points of opening, and closing .1 valve scavenging valve and, start-J In the scam ianvin drawin s: Fl ure l lr ii v- 23 mentary form ofthe valve gear with the parts ndifferent positions of? inovemen F1 s. Sandi show dia 'rammaticall aful. ther ClGYQlODBCliOlYDl of the valve gear shoiv 2, 3, fl andoshovf d'iagrammaticallyan ele l 100,

ing [its application to a two-cylinder engine having icnanksset at 180, degrees The i-WQi Figs, 61 and 7,,shoiving the gear, in "difi'eig-q. ently, set positions. ig. i .8 shovvs. a plan; viev. of the valve gear as it is applied; to a,

two-cylinder engine having cranksvatl8Qde-Il1Q grees. Riga-9 shows a front View of s same ever as shave shav n f0 release brackets removed.

ness the scavenging valve rollers and Fig. .10 shows an enlarged side View of one of the scavenging valve rollers andbracket shown in plan view in Fig. 8. Fig/11 shows a central longitudinal section through the axis of the valve gear'yoke and guiding frame, taken on the:

line:IX,' Fig. 8. Fig. 12'shows a similar section taken at right-angles to the section shown in Fig. 11 and taken on the line Y Y, Fig. 8. p 7

The same partsare designated by the same reference numbers in all the drawings.

Referring to Fig 1 which represents diagrammatically an elementary form of the.

gear, the crank shaft of the engine may be represented at 1, the line OO representing crank is on its outer dead center.

The pin-3, is connected by the link a, to the pin 5, carried by the sliding block 6,

which reciprocates on the gui es The pin 5, is also connected by the link 8, to the pin'9, which is carr ed by the reciprocating cam block 10. This caniyblock reciprocates on the guide '11, by'which it is confined to a 7 straight line movement.

Thecain block has the cam it and bearing against the surface ofthe block 10, and cam 12, are the rollers 13 and 14:. These rollers must be assumed to be confined by anyv suitable means to movements inthe line 15' and 16. The roller 13, represents the fuel valve roller or theroller movements of which, in the direction of the arrow 17, opens the fuel valve. *The roller 14-,represents the scavenging valve roller or the roller the; niovement'of which, in the direction of the arrow 17, opens the scavenging valve. 7 V i In the positionof theparts shown in Fig. 1, neither of the rollers 13 or 14,.are in contact withthe cam 12, and both fuel valve and scavenging valve are closed. If the pin"-3 and the connecting parts move to the positions as shown in Fig. 2, the block and cam reach one endoftheir: travel, and the fuel roller 13,1s raised, which opens'the fuel valve. In Fig. 31S shownthe relative positionof the cam and rollers at the opposite end of the cam block traveler when thepin 3, has reached the point at 180 de,-:

grees from theposition shown in Fig. 2,

the scavenging valve roller 1-1, is then raised V shaft tobe revolving in the direction of the 12, formed on arrow 18, When it will be seen that with thesetting of the gear" shown in Figs. 1

2 and 3, the center of the open period of the. fuel valve occur-s a short interval after the engine crank pin passes its inner dead center, and likewise the center of the open period of the scavenging valve occurs an [interval after the en ine crank in oasses its outer center. I i c Now the guides 7, the center line of which is indicated by the'line AA, are movable about the shaft 1 as center, and it will be seen that if they are shifted slightly from the positions shownuin Fig. 1, the angular lead which the engine crank pin has over the fuel valve and scavenging valve openings will be varied. Also it is seen that if the engine crank shaft is revolving in a pin with reference to the opening and closing of the valves, but such change in the angular position of the guides will also affect the extent of travel of the cam block 10, and cam 12, and vary the 'relation of such range of travel to the rollers 13 and 14:. This is an important feature of the gear. To clearly demonstratethis, in Fig.-

4 I show he 'uides moved to the an ular 7 b V a position ind cated by the line C'C. here shown the pin 3, is on the center line 'of theguides and all the parts are at one end of their travel. It is seen that in the range of travel given to the cam 12,,wlien the gear is in this position, the cam 12, will not come in'contactwiththe'roller 13,'at all,'and so in this position of the guides'T, thefuel valve is thIOWII'QUt of gear or not operated.

In Fig. 5,1 show the relative position of the cam and rollers when the pin 3, has reached the point at 180 degrees from the position shown in Fig. 4-, with the guides 7, in the same angular position as shown in Fig.

il-f The scaven in valve roller is where shown raised and it canbe readily seen that for this angular settlng of the guides 7, the

scavenging valve is opened for a" longer period than with the guide setting shown in Figs. '1, 2 and 3. It can now be understood .that the angular positions of the guides 7, indicated by the line A A, Fig.

1, represents a setting suitable for running the engine on fuel in the direction of the arrow, 18, as with this setting of the gear,

ion

setting vsuitable i for Sift the, directlen of. the

ehoiilcl ,be .at the ee:

ibOth feel :and yscavenging jyalvesy are aperetecl, and the; engine-1cranknpin has; m lee-d .-OVG1 the centen of; the -1D6ll0d 1015 J thefiopen engine on :lnel in' t'zi (1ireetionmppesite itoithet indicated by, the, erpew 18. i It; l similarly abe nnclerstoeclthat .tliemnguier position of the guides, shown in {Fig I'BPILQSGHESMQL the ,engine. in v N 18,; 354mm this not operated ht ell e held open, for

0d during-the setting, the. fuelv elve end the scavenging, w: eoneiclembly g 'e;1t,e1: turn of inward stroke .0 he orking, piston, giving the desired.- irelie 0';Yl1, CO1I1 PlQS sion in the cylindeir .,Theetarting air mite, eeliereinhefoi'ew stated should have the centei' of its pQijiQCl o/fpp iet zl8 fl de grees,,1"' m1 the enter oi, e mhie openingieo, when ell na rts" tem the positiens shown injiig l Valve 1. P iQdM eneninf Tlheq annen ofmepemtinggthe eta rting Hill Ye 1 will the k plai lately. "ileo can new be l lills tood Without ur h r xp wet m the he angular: Jim-e tion indicated-bye line D D;, in ep e s the tfil e it ieigeer' fm ing-the engine nthe 1: illOlMQPPQsi e te hat ind ce eiby them ,18. s lt-is seen thetthe settin'gg y n the OPSFM'f lgv termi e; 1

UIB -S MQIMJHPJ v ii ,ie openlng anclet the .ezune time p 'elonge th @Per e l f Wen t e 1 veng n alve The ff ect oi 1 1e 1,s,to keep the scsw ei eii veepj m the i l e 1 \etio' ke pf the: pieton e W il et t e-i altn 4 "the Sce ;enging veli etgg eerlg n, Fi s- 6 an LI;- "I eh i dia mmatic y a fmtfl e d i'e qpment Qf he gem and he e e 'ie t te etiw ia ndee nein wih WQ1l i I 1g CI'1Ill S Lt $01 degrees In Figs 6' en 7 he Wi ank shii z e 1- s ft retolving w'th, e 1: sheft of; theengine, is ehoivn at;.;l., f 3,, i s eenniegl a. sei e ,m tfil ee 9 mf l: v ind-ma r e a [Sli ing b o k =19 iv h h; el e in the we 2 which yokelin" m e ceritieidin ei tem 21,, inji lhich it is zr e fie 16 He i the tion b thef nte il 13 i ih ep e as i eme i le'ulmyrela 1 0mm thecen ter line X X es one of the vor gingerenk- Pie Q flieeneinelms o that h cylinde H he frame 21, Si heslm fl l: s we; any d ire angler PQ teixl ine of .the pins 122- Vancl 2:3, toethe; pine/26 and: 21?, gzespeetiw 17y, ,Which gins-J26 and ,2? ere; eel tiechb szthe;oscilletinghcanis, 2 8 and 29; re iepeeti, e151,; which earns oscillate 011., the ,cen- 138138 3 O 2I1ld;3l.1 Eeehohthe Cain-1s 287 and 29, is intended. to opeit-z te::t h e, fuelancLseavenging' \ZE1LVSA4OZE;;OI16;'OV,tilB cylinders: of :the engine, 2 As 5 the eylinclei's heme-t cranks; at 1805 degrees and the movements given, these pains hbywthee lmeehenism already; described are exactly/apposite, .01% out jot phase 180 clegiiees, the fuel: end so {H7811 ge Valves Will heeoi'lseetlyz operetech The cams L28 sin-c1529 eorresponel to. the; sliding bloeleancl vearn 1O IeHdlQ-imEignI; and the; Whole Ineeheniein shown in "Figs. 6 and 7;,istthe pra'cticel 1118,- elmnieel geqnimlent of that shown in vIEig. 1, with. 1 ee itein e additions. $011: the; fixecl cen; tens? 1l1l-'33, H.136: pivoted HBHIS carrying the/fuel?iizalveflrollers34L and 35,: B11Cl arms carrying: the scevengewelve rollers 86 and 317 5 fi heee rolle" rest; against fthe 'iiaces of the 63111528 and kQ anclYbytheir movements -i 'rem the eem cente zs 0118B the fuel mtenge; valv through, suitable eon,- nectiensz n. ,1 w

In the positions of all parts shownin Fig. i fi itheecam :28 has vlifted the oller 8i, and 4 the in el 3 valve of t the ieoi'respon ding (.eyh lllfiifil k f the; engine is ztherefore open.-

The

seayengewelve ofthe corresponding or opippsitencylinde g of fche engine is; therefore epenz. A starting iair Fit-1V6- ofi each ofthe eylinclere, gopemtecl-ibythe i olleie smncl 39; which? we ea-1nriecl byflevers pivoted on the fixed centers96 and 9% ln'ithis e i'enge ment .thewroller BQ aeted on by the: dam 29,, operates lt-hfi starting valve of the ffopposite eyl-inclel' o mthef: cylinder the-fuel and s caYenge, -.,\:elyes, of iW'illGll are oper eted by the'mtm '28,; and; likewise ":the roller- :88, 011-. erates the wstelzting JWZLLVQ v of 1 the cylinder which has its fuel and; eeavenge Welves opemteicl byithe 162M115 29m 1 e ltAvilL-be. seen that in the eng lai'; position of. theimme-QL, in Fig fl neither 1n .Eig. (Z, the -;f1'a 1ne 3 1,; S iyshifteclz (to new 4 angular ggposition end well pa nts are h wn :Qn Qf hei xt eme p iticnsl of tieyel, ltpwill he seen that; in thisvanguler set ngzof tl e een the ,fneleollel s Beand 35;. will not bel v.i 'd l: y t c m 2 8. and: uel e thel 'efore cnt out} m pe getive a $116, sc v egesielve have alonger period of opening and the rollers 38 and 39, are, in this angular setting of the gear, acted on by the cams 28'and 29,

' which cams are now pulled farther around opened by the roller 37, the proper action and relation is preserved. 7

It can now be seen comprehensively, that the gear provides a means ofva'rying the angular lead and follow of all valve operations with reference [to the engine crank, varies the duration of the open period of the scavenge valve to suit different angular positions, and also automatically renders the fuel and starting air valve inoperative outside of that range of angular relation to the engine crank which is suitable for their operation. I

In Fig. 6, the'line FF represents an angular setting of'the gear forrunning in the opposite direction tothat for which the gear 1 isshown set, and likewise in. Fig. 7, the

line GG,represents theangular setting of the gear for starting the engine 'in the opposite direction. It will be understood that a considerable range in the angular setting of the gear for either running on fuel'or for starting is allowable.

InFig. 8, I show a plan view of the gear as actually applied toa two-cylinderinternal combustion engine; the engine: having working cranks set at 180. degrees. Fig. 8 shows'the ends of the cylinders 10 and a1, of the engine which, for simplicity of de scription, I will assume to be a vertical en gine. Fig. 9 shows the front view of the same arrangement of gear as 18 shown in plan in Fig. 8. In Fig. 9 I show one side of I the cam ring .43, and the adjoining portion of the cylindercl, in section; and in Fig. 9,

all the scavenge'valves, scavenge valve rollers and supports'and the starting'air valve cams are, for simplicity, removed.

Referring to-FigsJ 8 and 9, the two ends of the cylinders 10 and ll, have four scavenge valves set in each, designated bythe numbers 1 1, l5, a6, 47, 418, 19, 50 and 51,

and arranged symmetricallyabout the centersofthecylinders. The fuel valves 52. and 53 are set in thecenter of eachof the cylin ders, and the starting air valves 54L and'55 are set at one side in the head ofeach cylinder. 7 The valve gear operating shaft 56, Fig. 9, is driven by any suitable means to revolve evenly with the crank shaft of engine and thisshaft carries at its upper and pin 57, Fig. 8. In Figs. 11 and 12, I show in two cross sections taken on lines XX' and YY,' respectively, in Fig. 8, the arrangement of the parts now described and which are shown in plan in Fig. 8. The pin,

'57, carries a sliding block 58, which slides in the yoke 59. V This yoke is guided to reciprocate in a slide formed. in the cover 60 of the circular gear box 61. In Fig. 8, the cover 60 is removedin order to show the yoke and place clearly in Figs. 9, 11 and 12. The yoke 59 carries the pins 62 and 63, which are connected by the links 6% and 65 to the pins 66 and 67 in the oscillating cam rings 12 and 13. These cam rings I show made in two parts, secured together as shown in'the secother parts beneath it, but it is shown in tional part of the Fig. 9, an upper parton which the cams for operating the scavenge valves are formed and a lower supporting part which rests on the ledge found on the cylinders. These cam rings, it'is seen, encircle all that portion of the cylinder heads in which the scavenge, fuel, and starting air valves are placed. On the upper portion of each of the cam rings 12 and 13, are formed four cams for operating the scavenge valves, which cams at oneend of'the oscillation of the rings act on the scavenge valve rollers 68, 69, 70,71, 72, 73, 74: and 75. The roller 68 is shown held in'place by a lever- 76, and

bracket 77, but the levers and brackets of all the other'scavenge'valve rollers are, for simplicity, removed. These rollers 69 to 75, in-

elusive, the meansof support or attachment of which are not shown, it will be understood are constrained to move as is the roller '68, in planes passing through the axis of their respectivevalves. The detail of these levers and brackets andthe manner in which the movement of the rollers is transmitted to the scavenge valves is shown in Fig. 10,

As there shown, the lever 76, is pivoted on the pin 78, which is carried by the bracket 77, which bracket is secured to the cylinder head. The roller 68, is carried by one end of the lever 76 and; bears against the cam ring I 4:2, while the other end of the lever carries a set screw 79, which acts on the end of the stem of the scavenge valve 1 1. The fuel valves 52 and 53, in the center of the cylinders 40 and 41, are operated from the cam rings by means of the oscillating arms 80 and 81, which are in sliding engagement at their outer ends with the pins 98 and 99, which are fixed in the cam rings l2and 43. The mechanism bywhich the movement of these arms is made to open and-close the fuel valves at one end of the swing or oscillation of the arms is immaterial. "I have shown, however, the fixed bodies of the fuel valves to have cut (on them, steep pitch screw threads and on these threads the sleeves 82 and 83 turn. These sleeves are formed .inteendthe crank gral with the arms 80 and 81 and the yokes ingthe scavenge valves to bG-01)I1(3Cl,Whll

at the opposite end of the oscillation of the cam rings, the fuel valvesza-re openedbythe connections described. i

- WVith the setting of the gear shown 1 in Figs. 8 and 9, the starting air valves Stand are not. operated at all, vas the setting shown is for running on fuelr Q'lhe two starting air valves54c andi55, are operated bythe single rocking lever 8 8,which: is piv-v otedon thecentral pin 89, suitably carried bythe cylinders or fraine of the engine. The two opposite ends of thelever 88 carry set screws which areadjusted to just; clear the end of the stemsof the starting valves The two opposite sides of thelever 88, also car'ry rollers9Oand 9lw P 4 On the lowerportioirof the oam rings l2 and-43, :are secured two 1 cams 92 anda93,

which are-shown'in plan in Fig.8, but which are "removed in-Figi-Q, andwhich with the setting of the gear shown in Fig. 8 do not act upon anything- Then; however, the gear box (51,is turned to the prop r angular position for startingtheengine, the cam rings 4'2 and 43 are givenga' differentrange ofoscillation and the cams-92 and 93- then come in contact with the rollers 90 and respectively. I It is seen 'that if the scam ring 42 beposcillated far enough in the directicn, of the arrow 94, the earn 92, will act against the under side of the roller 90, raise that end of the l'ever 88' and cause to be pushed down the-stem of the starting 'air valve=551 Similarly the'cam- 93 will operate the valve 54:. The gear box 61"wis carriedby the bracket 95, Fig. 9, which ispartof the cyl inders orframe of the engine.-- As is shown inthe sectionalviewsfFigsnll' and lil, the

gearbox may be turned in this support and maybe set-to any, angular position desired;

--The means of-"turn'in gthegearbox and of holdingit in the position 'des1red,*I have not indicated as any suitable means may be employed. r 1 I It is now'seen' that the design of the valve gear shown in rigs. 8 to 12, performs! all the functions hereinbefore indicated and shown diagrammatlcally in Figs 6 and 7.

Thus,in the setting'shown in Figs-S and 9,

the scavenge valves and fuel, valves a're operated at opposite points'of'the revolutionturned to the proper angular position giving the proper differentrange tothe oscilr: lation .to the cam rings, the fuel valveswill. not beoperated at (all, asthei arms and Slavill not be swung far enough to raise the yokes. Stand to contact withthenuts ,86 and 87 on the valve stems,.while in such changed range of oscillation of thecain rings,the'cams 92 and 93 will act on, the, rollers and 91 and so operate the starting: valves and 55. Thus while the shifting of the gear .box 61, about the shaft..56 as; a center, gives the necessary change. of angular lead with reference to the engine crank to the operation of the valves for starting on air and for running on fuel, this angular adjustment also serves at the same time by giving to the rings 42 and i and anhentirely diiferent range and position of movement, to properly throw out and in the operation of the starting air and fuel valves,

and to properly. vary the duration of the openingofithe scavenge valve. i H

i. It should be noted thatthe oscillating cam rings, encircling all the scavenge valves, ,enables a plurality of scavengeivalves to be. operated in a-verysimple manners; also that the: thrust of u the scavenge valve rollers balance each other on the cam ring inthe arrangement shown,v a v V, Inconnection with the following claims will be understoodithat, while I have em= ployed terms more or lessspecific in, refer: ring to the structural p artsv of my invention; I do not limit myselfto these parts .as herein, shown and described but include within. said, terms any .equivalentsthatwill accomplish substantially the same results.

'VVhatI claim is: e i 4 V lnlni a valve gear, the combination of a revolving shaft, a reciprocating Apart derive ing its rechorocating motion from. the said. revolving shaft, guides in. which the said, part reciprocates ithe said guides being. angularly adjustable about the said; shaft. as a center, a cam having cyclicmotion, and a l-inle connecting the said reciprocating part with the said cam. i 1 2; In a valve gear, the combination of a reciprocating part moving in suitable guides and deriving itsreciprocating motion from a revolving shaft, a-cam having cyclic 1110- I tion a link connecting the saidcamto the passingthrough the aXis-of-the said shaft and being angularly movable or adjustable about the axis got the -Sfi'1Cl' shaft as a center,"

a cam or cams having cyclic motion, andya link transmitting motion from the said reciprocating part to the said cam or cams.

; 4. 111 a valve gear, the combination of a revolving shaft carrying a crank and crank pin, a reciprocating yoke havingv a slot or slide at "right angles to its direction of re ciprocation the said crank pin engaging in the said slot or slide, a cam having cyclic motion, a link connecting the said cam with the said yOl Q,'1-11Cl. a guide frame in which the said yoke reciprocates, the said guide frame being angularly adjustable about the said shaft as a'center.

' grees 5. In a valve gear for a two cylinder engine having working cranks set'a't' 180 dein, two oscillating cams, two links, each one of said links connecting one of the two opposite ends of the said yoke to one of the oscillating cams, a guide frame in which the said yoke reciprocates, the said guide frame being 'angularly adjustable about the said shaft as a center.

6. In a valve gear for atwo-cylinder engine, the combination of .a' revolving "shaft,

a reciprocating part derivingsmotion from the said revolving shaft, a guide frame in which the said reciprocatingpart moves, the said guide frame being angularly adjustable about the said shaft as a center, two oscillating cams, and a link connecting each of the two oscillating cams to a point on the said-reciprocating part, which points are on opposite sides of the axisof the said revolving shaft. r

. 'Z. In a valve gear for a two-cylinder engine, the combination of a revolving shaft,

is a reciprocating yoke deriving motion from connecting the said oscillating the said revolving shaft, the center line of the axis of the said shaft, two oscillating parts, two links parts, to.

the said yoke intersecting points onthe center lineof the said yoke,

- ternal combustion engine, the combination ofa fuel valve and starting air valve for i each-cylinden'a reciprocatingpart, two osthesaid two points being on opposite sides 'ofvthe axis of thesaid shaft, and a guide frame in. which the said yoke reciprocates, the said guide frame being an ularly adjustable about the axis of the said shaft.

8. In ayva'lve gear. for a, two-cylinder incillating cams deriving motion from r the said reciprocating part through suitable d mechanism between the connections, an

said cams and the said valves whereby each;

one'of the saidcanis operates the fuel, valve of one of the sa d cylinders and the starting air valve of the other of the said cylinders:

9. In a valve gear for a two-cylinder in ternal combustion engine, the combination I of a fuel valveand a starting air valve for from each other, the combination of a revolving shaft carrying a crank pin, a

reciprocating yoke engaging the said crank each cylinder, two working cranks set at 180 degrees apart, a reciprocating yoke'de- I riving motion from a shaft, two oscillating cams connected by'linksto opposite ends of the said reciprocating yoke, a guide frame for said yoke angularly adjustable, about the said shaft, and mechanism between the cams and valves through which one of the said cams operates the fuel valve of the first cylinderand the starting air valve of the second cylinder, and the other ofsaid cams operates the fuel valve ofthe second cylinder, and the starting air valve of the first cylinder. 3

10. In a valve gear for a two-cylinder engine, the combination of a fuel valve and a, starting'air valve for each cylinder,- two partshaving cyclic motion, one of the said parts being carried on each of said cylinders and operating the fuel valve of the cylinder onwhich it is carried, and'a single rocking lever having oppositely extending arms and,

mounted between the saidcylinders, each of thearms of said lever operating the starting air valve of one of saidcylinders, said bustion engine, the combination of a' plu-- ralityof scavenging valves in thefcylinder head of the engine, an oscillating ring mounted on the cylinder head and encircling said valves, cam pro ections on the said ring, rollers acted on, by the said cam projections, and levers for transmitting the movement of the said rollers to the said valves. 7 V V 13. In a valve gear for aninternal com bustionengine, the'combinationof a scavenge valve or valves and-afuel valve or valves in the cylinderhead ofthe engine, an oscillating ring mounted on the cylinder headland encircling the said valves, and

connections between the said valves and the said ring, the said connections transmitting motion. from the said ring 'tothe'said-scavenge valves to openthe said scavenge valves at one end of the oscillation of the said ring and transmitting motion from the said ring to the said fuel valves to open the said valves at the opposite end of the oscillation of the said rin 14. In a valve-gear for an internal com-.

bustion engine, the combination of valves the cylinder head of-th'e engine, an oscillatingring mounted on the cylinder head and; encircling the said valves having its axisof oscillation coinciding wither parallel to the aXis of the cylinder, and levers mounted to transmit motion from said ring to said valves to operate the same.

15. In a valve gear for an engine, the combination of valves in the cylinder head of the engine, a reciprocating yoke deriving motion from a shaft, an oscillating ring mounted on the cylinder head and encircling said valves, a link connecting the said ring to said yoke, a frame guiding said yoke and angularly adjustable about the said shaft, and mechanism for transmitting motion from the said ring to the said valves.

16. In a valve gear for a two-cylinder in ternal combustion engine, the combination of fuel valves and starting air valves in the cylinder heads of the engine, an oscillating ring mounted on each of the cylinder heads and encircling its valves, and connections for transmitting motion from each of the said rings to the fuel valve of one of the cylinders and for transmitting motion from the same ring to the starting air valve of the other of the said two cylinders.

In Witness whereof, I hereunto subscribe my name, this 2nd day of November A; 1).,

GEORGE K. DAVOL. Witnesses:

WV. l/V. KEALEY, G. M. PAGE.

Copies of this patent may be obtained for five cents each, by addressing the Commissioner of Patents, Washington, D. G. 

